As is known, an electric motor has a stator part and a rotor part, mounted so as to move in said stator part. The electric motor furthermore has an output shaft which is linked in rotation with the rotor part.
In order to measure the angular position of the shaft of an electric motor, it is known to use a position sensor known to the person skilled in the art by the term “resolver”.
With reference to FIG. 1, an electric motor 10 having a stator part 11 and a rotor part 12 connected to an output shaft is represented schematically. A position sensor 6 is mounted in a fixed fashion with respect to the stator part 11 of the motor 10 and is adapted to detect the position of targets 3 fixed to the rotor part 12 of the motor 10, as illustrated in FIG. 1. As is known, the detection of the position of the targets 3 by the position sensor 6 is carried out by measurements of voltage between at least one emitter winding and one receiver winding of said sensor 6.
Some motor vehicle architectures have two electric motors in order to make it possible, for example, to power the two driving wheels of the vehicle independently. When they are integrated in the motor vehicle, and the two electric motors are arranged beside one another and their respective position sensors are very close together.
This results in the occurrence of interference between the two position sensors. By way of example, magnetic coupling may occur between an emitter winding of the first position sensor and a receiver winding of the second position sensor, which affects the precision of the measurement of the angular positions of the motors.
In order to eliminate this drawback, a first solution would consist in distancing the position sensors from one another, but this cannot be done in view of the compactness requirements of current motor vehicles. A second solution would be to install an insulating barrier between the two position sensors of the two motors. In practice, such an insulating barrier is liable to generate magnetic perturbations within each position sensor. Furthermore, the use of two independent sensors entails a high cost. Such a solution also cannot be adopted.
It is therefore an object of the present invention to overcome at least some of these drawbacks by providing a single position measurement device capable of precisely and reliably measuring the angular position of at least two motors close to one another.